CN112312390B - Neighbor discovery method and system - Google Patents
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W40/00—Communication routing or communication path finding
- H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
- H04W40/04—Communication route or path selection, e.g. power-based or shortest path routing based on wireless node resources
- H04W40/10—Communication route or path selection, e.g. power-based or shortest path routing based on wireless node resources based on available power or energy
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W40/00—Communication routing or communication path finding
- H04W40/24—Connectivity information management, e.g. connectivity discovery or connectivity update
- H04W40/246—Connectivity information discovery
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W40/00—Communication routing or communication path finding
- H04W40/24—Connectivity information management, e.g. connectivity discovery or connectivity update
- H04W40/248—Connectivity information update
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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Abstract
The invention provides a neighbor discovery method and a neighbor discovery system, wherein the method comprises the following steps of: scrambling the data by adopting a scrambling code, and transmitting the data to a receiving node so that the receiving node extracts the scrambling code from the data and detects the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code. When applied to a receiving node, the method comprises the following steps: receiving data transmitted from a transmitting node, wherein the data is scrambled by the transmitting node in advance by adopting a scrambling code; extracting a scrambling code from the data, and detecting the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code. The invention uses the scrambling code to scramble the transmitted data, fully utilizes the one-to-one correspondence relation between the scrambling code detection distance which is far greater than the data transmission distance and the scrambling code and the user, expands the neighbor detection range of the network node, ensures that the node can detect the neighbor nodes outside the 2-hop range only through the broadcasting of the 1-hop HELLO message without additional expenditure, and establishes and updates the multi-hop neighbor information list.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a neighbor discovery method and system.
Background
In wireless networks without centers such as a mobile self-organizing network, a sensor network and the like, main functions of neighbor discovery include neighbor interception, establishment and maintenance, and information such as neighbor relation of nodes, state of neighbor nodes and the like is obtained through interaction of neighbor discovery data among the nodes, so that a foundation is provided for topology control, routing, data transmission and the like of the network.
In the existing wireless network networking technology, the establishment of a neighbor relation and the acquisition of the neighbor node state are mainly obtained by periodically broadcasting own and neighbor information by a node, and researchers usually refer to the information as a Hello message. Nodes in the network firstly judge the link state among the nodes by exchanging Hello messages, and establish or update the 1-hop neighbor relation and state among the nodes; broadcasting the established and collected 1-hop neighbor relation and state in the range of N hops according to the requirement, and simultaneously receiving, processing and forwarding the neighbor relation and state broadcasted by other nodes; and finally, establishing and collecting neighbor relation and state of the N+1 hop with the N+1 hop taking the N as the center according to the received broadcast message.
According to the existing neighbor discovery method, the node establishes neighbor relation and state information of N+1 hops, related information needs to be broadcast in the range of N hops, and system overhead and network burden are increased. In addition, the existing neighbor discovery method does not sufficiently consider and utilize the relationship between the transmission distance and the transmission rate, and does not sufficiently consider the security problem of wireless transmission.
Disclosure of Invention
In order to solve the above problems, embodiments of the present invention provide a neighbor discovery method and system that overcomes or at least partially solves the above problems.
According to a first aspect of an embodiment of the present invention, there is provided a neighbor discovery method, applied to a transmitting node, including: scrambling the data by adopting a scrambling code, and transmitting the data to a receiving node so that the receiving node extracts the scrambling code from the data and detects the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code.
According to a second aspect of the embodiment of the present invention, there is provided a neighbor discovery method applied to a receiving node, including: receiving data transmitted from a transmitting node, wherein the data is scrambled by the transmitting node in advance by adopting a scrambling code; extracting a scrambling code from the data, and detecting the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code.
According to a third aspect of an embodiment of the present invention, there is provided a neighbor discovery system, the system including: a transmitting module and/or a receiving module; the sending module is used for carrying out scrambling processing on the data by adopting the scrambling code and sending the data to the receiving node so as to enable the receiving node to extract the scrambling code from the data and detect the energy of the scrambling code; establishing a neighbor list according to the energy of the scrambling code; the receiving module is used for receiving the data sent from the sending node, and the data is scrambled by the sending node in advance by adopting a scrambling code; extracting a scrambling code from the data, and detecting the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code.
According to a fourth aspect of embodiments of the present invention, there is provided an electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the neighbor discovery method as provided by any one of the various possible implementations of the first aspect when executing the program.
According to a fifth aspect of embodiments of the present invention, there is provided a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a neighbor discovery method as provided by any one of the various possible implementations of the first aspect.
The neighbor discovery method and the neighbor discovery system provided by the embodiment of the invention have the following beneficial effects:
1. the node uses the scrambling code to scramble the transmitted data, fully utilizes the characteristics that the scrambling code detection distance is far greater than the data transmission distance, the one-to-one correspondence between the user and the scrambling code and the like, expands the neighbor detection range of the network node, ensures that the node can detect neighbor nodes outside the 2-hop range only through the broadcasting of the 1-hop HELLO message without additional expenditure, and establishes and updates a multi-hop neighbor information list.
2. The relation among the transmitting power, the transmission distance and the transmission rate is fully considered and utilized, and the data transmission distance is estimated in a self-adaptive way by establishing the relation between the receiving power of the detectable scrambling code and the 1-hop and 2-hop neighbors of the successfully transmitted and received data.
3. The data scrambling also enables the network to have a certain encryption communication function, so that the security of the system is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
Fig. 1 is a schematic view of coverage of a transmitting user provided in the prior art;
fig. 2 is a schematic diagram of coverage areas of control channels and traffic channels of a control node, a mobile user provided in the prior art;
FIG. 3 is a schematic diagram of a topology structure at different transmission rates provided by the prior art;
FIG. 4 is a graph showing a typical relationship between transmission rate and transmission distance provided by the prior art;
fig. 5 is a schematic flow chart of a neighbor discovery method according to an embodiment of the invention;
fig. 6 is a schematic diagram of a neighbor discovery process based on scrambling codes according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a neighbor relation of a node S according to an embodiment of the present invention;
fig. 8 is a schematic diagram of a neighbor information transfer process according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of node distance estimation and grouping according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of a neighbor discovery system according to an embodiment of the invention;
fig. 11 is a schematic diagram of an entity structure of an electronic device according to an embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Aiming at the problems in the prior art, the embodiment of the invention provides a neighbor discovery method based on scrambling codes. The terms present in the method will first be described:
1. scrambling
Scrambling is a processing method of digital signals, that is, a scrambling code is multiplied with an original signal, thereby obtaining a new signal. The new signal is scattered in time, frequency compared to the original signal. Thus, scrambling is also a modulation technique in a broad sense. The inverse operation of scrambling is called descrambling.
Scrambling technology is widely used in digital communications, and is mainly used for four purposes:
1) In order to prevent the original signal from generating continuous 0 or 1, the probability of successful reception of a receiving end is increased;
2) Encryption, such as in GSM, WCDMA, LTE, scrambling may implement part of the communication encryption function;
3) Spreading, in CDMA technology, scrambling is used to spread the original signal;
4) In CDMA technology, scrambling codes are used to distinguish between different devices.
In addition, to achieve the above requirements and functions, the scrambling code employed by the scrambling technique is typically a pseudo-random sequence.
2. Relation of transmission power, transmission distance and transmission rate
It should be noted that there is a relationship between the transmission power, the transmission distance, and the transmission rate, which is such that: under the condition of a certain transmitting power, the maximum transmission rate is inversely proportional to the maximum transmission distance, namely, the higher the maximum transmission rate is, the smaller the maximum transmission distance is; under the condition of a certain transmission rate, the maximum transmission power is in direct proportion to the maximum transmission distance, namely, the higher the maximum transmission power is, the larger the maximum transmission distance is; and in the case of a certain transmission distance, the maximum transmission power is proportional to the maximum transmission rate, i.e., the higher the maximum transmission power, the higher the maximum transmission rate. Therefore, in the power control and link adaptation processes, the transmission distance of the traffic channel changes, resulting in corresponding changes in the topology of the traffic channel of the network. Meanwhile, in the networking and packet transmission processes, the requirements of different transmission channels and different packet types on transmission quality are different, and the transmission parameters such as the transmission rate and the like which are required to be adopted are also different, so that the corresponding transmission distances are obviously different.
In summary, power control, link adaptation policy, specific qos requirements, etc. may cause different transmission distances for different packet transmissions between the same users, which increases the difficulty of resource coordination and allocation. For a better understanding of the model of the relationship between users, definitions of transmission range, interference range, and carrier sense range are given below:
1) The transmission range (transmission range, tx_range) is the range within which the transmitted packet can be successfully received. This transmission range is mainly dependent on the transmit power and the radio propagation characteristics.
2) The physical carrier sense range (physical carrier sensing range, pcs_range) is a range within which other stations can detect transmissions. It depends mainly on the sensitivity and radio propagation characteristics of the receiver.
3) The interference range (interference range, IF range) is the range in which stations in the receiving state are interfered by a transmitter and are subject to loss. The interference range is typically larger than the transmission range and is a function of the distance between the transceiving users and the path loss model, which is difficult to predict.
Referring to fig. 1-2, as can be seen from the above analysis, power control is closely related to network connectivity. The larger the user transmission power, the larger the communication radius, the larger the number of optional neighbor nodes, the easier the connectivity is ensured, but the larger the energy consumption and the stronger the communication interference are. Conversely, the smaller the user transmit power, the smaller the communication radius, the fewer the number of optional neighbor nodes, the more difficult the connectivity assurance, but the lower the energy consumption of the user and the inter-user interference will be. In addition, the user does not have to establish communication links with all the neighbor nodes, and the neighbor nodes are appropriately selected and selected, so that the cost of a routing protocol, an MAC protocol and the like can be reduced.
Assuming that the transmitting power of the transmitting user is 50W, the height of the transmitting antenna is 15 meters, and the height of the receiving antenna is 3 meters, the following communication distances can be achieved by the existing typical device under the condition of medium relief topography:
under the condition of 128kbps speed, the maximum communication distance is not less than 20km;
under the condition of 2Mbps rate, the maximum communication distance is not less than 10km;
and under the condition of 16Mbps rate, the maximum communication distance is not less than 5km.
As shown in fig. 3, the topological relationship between users at the user transmission rates of 128kbps and 16Mbps is given. It can be seen that when the user transmits at a low rate, the overall network can maintain a better connectivity; and when the user transmits at a high rate, the number of neighbor nodes with which high-speed communication can be performed is greatly reduced. As is clear from the above examples, when the conditions such as the transmission power and the height of the transmitting/receiving antenna are identical, the higher the transmission rate between the transmitting/receiving users is, the longer the maximum communication distance is.
More generally, assuming a simple free space propagation model and assuming power attenuation to transmission distance power of Cheng Zhengbi, the transmission rate and transmission distance are fitted to obtain a typical relationship between transmission rate and transmission distance as shown in fig. 4.
The embodiment of the invention provides a neighbor discovery method, which has the following core ideas: the node uses the scrambling code to scramble the transmitted data, and uses the characteristics that the scrambling code detection distance is far greater than the data transmission distance, the one-to-one correspondence between the user and the scrambling code and the like to transmit the user identity information, so that the node can detect the neighbor nodes outside the 2-hop range without additional expenditure, and meanwhile, the scrambling also enables the system to have a certain encryption communication function, and the safety of the system is improved.
The basic assumption and premise of the scrambling code-based neighbor discovery method are as follows:
1. there are multiple users in a wireless network or subnetwork, and the users interact signaling through control channels to coordinate and control network resources.
2. Users in the network allocate control channels through mutual coordination or according to a predefined rule, so that control channels among users are ensured not to collide in the wireless network or the subnetwork.
3. The user in the network uses the predefined scrambling code to scramble all the transmitted data, and the user and the used scrambling code have a one-to-one correspondence relationship, i.e. the identity of the user transmitting the data can be determined by the detected scrambling code.
4. The packet data sent by the users contains known specific sequences, such as a synchronous sequence or a pilot sequence, which are used for synchronization, channel estimation and the like in the communication process between the users, and the specific sequences are independently scrambled in the scrambling process.
5. The physical or logical separation of the control channel and the service channel is allowed, and the control channel adopts measures such as low code rate, constant power, interference resistance and the like, so that the low speed, high reliability and large coverage are realized as much as possible; the service channel has link self-adapting capability, the transmission rate and the coverage range are dynamically changed, the corresponding maximum coverage range is small when the transmission rate is high, and the corresponding maximum coverage range is large when the transmission rate is low.
The neighbor discovery method provided by the embodiment of the invention is applied to the sending node and comprises the following steps:
scrambling the data by adopting a scrambling code, and transmitting the data to a receiving node so that the receiving node extracts the scrambling code from the data and detects the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code.
Correspondingly, referring to fig. 5, the embodiment of the present invention further provides a neighbor discovery method applied to a receiving node, including but not limited to the following steps:
step 101, receiving data transmitted from a transmitting node, wherein the data is scrambled by the transmitting node in advance by using a scrambling code.
102, extracting a scrambling code from data and detecting the energy of the scrambling code;
step 103, building a neighbor list according to the energy of the scrambling code.
Wherein, as an optional embodiment, the neighbor list is an n-hop neighbor list, n >2; accordingly, establishing a neighbor list according to the energy of the scrambling code includes:
establishing a 1-hop neighbor list and a 2-hop neighbor list through a 1-hop Hello message with a neighbor node;
establishing an n-hop neighbor list according to scrambling code information, wherein n is more than 2;
the distance between the nodes is defined based on the energy of the scrambling codes, and the n-hop neighbor list is divided into m groups according to the distance according to the 1-hop neighbor list and the 2-hop neighbor list.
Specifically, referring to fig. 6, the following describes an interaction procedure between a transmitting node and a receiving node:
under the assumption condition, the neighbor discovery method based on the scrambling code provided by the embodiment of the invention realizes neighbor discovery through the following processes:
firstly, a node scrambles transmitted control data and service data by using a pre-designated scrambling code, and a 1-hop neighbor list and a part of 2-hop neighbor list are built through 1-hop Hello message interaction with neighbor nodes;
step 2, then, the node extracts the scrambling code from the received control data and service data, extracts the possible scrambling code in all possible receiving channels, records and updates the detected scrambling code information list, and establishes an n > 2-hop neighbor list by using the known 1-hop and 2-hop neighbor lists;
and 3, finally, estimating and quantifying the energy of the detected scrambling codes by the nodes, defining the distance between the nodes according to the energy of the scrambling codes, and dividing the n-hop neighbor list into m groups according to the distance by referring to the known 1-hop and 2-hop neighbor information.
Through the above procedure, the node can build a 1-hop and 2-hop neighbor list, m n > 2-hop neighbor lists. As shown in fig. 6, nodes in the network expand the neighbor interception range of the conventional neighbor discovery strategy through interaction of Hello messages and extraction of scrambling codes, and classify the ascertained multi-hop neighbor nodes to form a plurality of neighbor lists divided according to communication distances (hop counts). These neighbor lists may be used for routing during data transmission, etc., as shown in fig. 7.
Based on the foregoing embodiment, as an alternative embodiment, the scrambling manner in the sending node may specifically be the following manner:
the network node obtains scrambling sequences corresponding to the identity information of the network node one by one in the network building or network access stage, and any node in the network is ensured to know the corresponding relation between the node identity and the scrambling sequences. The specific scrambling code coordination and allocation scheme is not limited here, provided that the nodes in the network know the corresponding information in advance.
Assuming that the number of chips of the scrambling sequence consisting of 0, 1 is l_0 and the duration is t_0, the duration of one chip, i.e., the duration of one 0 or 1, is t_0=t_0/l_0. The node is assumed to perform baseband processing on the transmitted data according to the network environment and own requirements, and the single bit duration of the binary data sequence formed before scrambling is t_1.
If t_0=t_1, then scrambling is employed with the scrambling formula d '= (d+p) mod2, where d is one bit of the data sequence, p is one bit of the scrambling sequence, and d' is one bit of the scrambled data sequence. Specific examples are shown in the following table.
Table 1 data sequence scrambling example 1
If t_0+.t_1, each bit of the data sequence d and the scrambling sequence p is spread into a plurality of identical bits such that the duration tx_0=tx_1 of one bit of the spread sequence data sequence d_x and the scrambling sequence p_x is then scrambled using the scrambling formula d' = (d_x+p_x) mod 2. The following table gives an example of data sequence scrambling in the case of t_0=t_1/3.
Table 2 data sequence scrambling example 2
In general, a multiple relationship between the duration of one bit of information of the data sequence and the scrambling sequence should be ensured as much as possible in order to facilitate data scrambling by a simple sequence operation. Furthermore, the data sequences here comprise known specific sequences and the known specific sequences are individually scrambled as specific components of the data sequences, i.e. during descrambling, these known specific sequences can be detected and descrambled independently.
Based on the foregoing embodiment, as an optional embodiment, the neighbor discovery method applied to the transmitting node further includes: periodically or according to the need, writing the collected neighbor information into the Hello message; the Hello message is sent to the 1-hop neighbor node.
Specifically, for the neighbor information transfer process, the neighbor information transfer in the network is performed in two ways: explicit HELLO messages and implicit scrambling codes. The node writes the collected neighbor information into HELLO information periodically or according to the need, then sends the information to the 1-hop neighbor node, and directly transmits the neighbor information in a control signaling mode; meanwhile, the node scrambles the transmitted control data and service data, and other nodes can indirectly obtain the information of the neighbor nodes by detecting scrambling code information.
The neighbor information transmission process is shown in fig. 8, the HELLO message carries neighbor information of the node and is transmitted in a 1-hop range of the sending node, and the receiving node can obtain relevant information only after correctly receiving and reading the specific content of the HELLO message; accordingly, the method of obtaining neighbor information by detecting the scrambling code does not need to read specific information of the transmitted data, and only needs to determine information of the scrambling code sequence used in the data transmission process, and then map the scrambling code sequence to a corresponding node.
For detection of scrambling sequences, this is mainly done by known specific sequences and possible scrambling code information sent by the nodes. As an alternative embodiment, before extracting the scrambling code from the data, the method further comprises: based on a pre-agreed scrambling strategy, generating a scrambled specific sequence according to a pre-acquired specific sequence and a scrambling code; performing correlation processing on the received data by adopting a sequence to obtain a correlation value; if the correlation value exceeds the preset threshold, the confirmation data is scrambled by adopting a corresponding scrambling sequence.
Specifically, a simple and feasible way may be: the receiving node generates a specific sequence after scrambling according to the known specific sequence and possible scrambling codes and a scrambling strategy in a local mode, then uses the sequence to correlate with a received signal, and judges whether the corresponding scrambling sequence is adopted for scrambling according to the magnitude of a correlation value. If the correlation value exceeds a given threshold, the received signal is considered to be scrambled by adopting a corresponding scrambling sequence; if the correlation value does not exceed the given threshold, the received signal is considered not scrambled with a corresponding scrambling sequence, at which point the scrambling sequence is changed to repeat the above procedure.
For node distance evaluation and grouping, through the neighbor information transfer process as above, nodes in the network can obtain 1-hop and 2-hop neighbor information and a detected scrambling code information list. The node evaluates the distance between itself and the detectable neighbor according to the information, and further groups the neighbor according to the distance evaluation, and the specific process is as follows:
1. and according to the information of the 1-hop neighbor N (1) and the 2-hop neighbor N (2), counting the detected scrambling code power information E (1) and E (2) corresponding to the neighbor identities, and performing the statistical calculation to obtain the statistical average, the maximum value, the minimum value and the like of the detected scrambling codes.
2. And according to the wireless transmission large-scale fading model, establishing a relation f (d, e) between the wireless transmission distance and the received signal power, wherein d represents the distance between nodes, and e represents the signal power received by the nodes.
3. Assuming that the network node transmits a known specific sequence using the same power p_0 and the processing gains of the transmitting node and the receiving node are known, the scrambling code power E (N) detected in the scrambling code information list is quantized according to information such as f (d, E), N (1), N (2), E (1), E (2), and the like, and the actual distance is expressed in terms of hops between nodes in the quantization process.
4. And dividing neighbor nodes which can be detected by the nodes into 1-hop neighbor N (1), 2-hop neighbor N (2), 3-hop neighbor N (3), …, (m+2) -hop neighbor N (m+2) and the like according to the scrambling code power E (N) detected in the quantized scrambling code information list, completing distance evaluation and grouping of the neighbor nodes, and establishing a multi-hop neighbor list.
5. Through node distance evaluation and grouping, the network node establishes an (m+2) hop neighbor list according to the displayed and implicit neighbor information exchange and detection, and provides information and basis for mechanisms such as routing, data transmission and the like. In addition, in the process of quantizing the detected scrambling code power, historical statistical information can be fully utilized to optimize and correct the quantized result, so that the virtual distance between nodes expressed by hops is more accurate.
In summary, the neighbor discovery method provided by the embodiment of the invention has at least the following beneficial effects:
1. the node uses the scrambling code to scramble the transmitted data, fully utilizes the characteristics that the scrambling code detection distance is far greater than the data transmission distance, the one-to-one correspondence between the user and the scrambling code and the like, expands the neighbor detection range of the network node, ensures that the node can detect neighbor nodes outside the 2-hop range only through the broadcasting of the 1-hop HELLO message without additional expenditure, and establishes and updates a multi-hop neighbor information list.
2. The relation among the transmitting power, the transmission distance and the transmission rate is fully considered and utilized, and the data transmission distance is estimated in a self-adaptive way by establishing the relation between the receiving power of the detectable scrambling code and the 1-hop and 2-hop neighbors of the successfully transmitted and received data.
3. The data scrambling also enables the network to have a certain encryption communication function, so that the security of the system is improved.
In order to better illustrate the neighbor discovery method based on the scrambling code, particularly the node distance evaluation and grouping process provided in the above embodiment of the present invention, the neighbor discovery process is further described below by way of example of a network as shown in fig. 9. As shown in the figure, it is assumed that the node S periodically transmits HELLO messages, where the HELLO messages include node self information and collected 1-hop neighbor information of the S node, and the node S receives HELLO messages transmitted by other nodes. After a certain time of interaction of HELLO information, the node S may establish its 1-hop neighbor list N (1) = [ R2, R6, R7] and 2-hop neighbor list N (2) = [ R1, R10, R11, R12], and collect corresponding neighbor node information, including but not limited to link rate, connection status, etc.
Meanwhile, it is assumed that the node S detects a known pilot sequence and all possible scrambling sequences on all reception channels based on the known information. The node S scrambles the known pilot sequences with possible scrambling sequences, generates local detection sequences s_t1, s_t2, … …, s_tn, and correlates the signal of the received channel with the local detection sequences, detects whether the correlation peak exceeds a detection threshold th_0, and if so, considers that the corresponding scrambling sequence is detected. According to the relation between the transmission distance and the transmission rate, the transmission distance of the known sequence which can be detected by using the detection mode is far longer than the transmission distance of the actual data. As shown, the node S may eventually obtain a list of detected scrambling code information s_t= [ R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15], including but not limited to power information of the detected scrambling code sequence.
Through the above neighbor information transfer process, the node S obtains a 1-hop neighbor list N (1), a 2-hop neighbor list N (2), and a scrambling code information list s_t. On this basis, the node S assumes that all nodes in the network transmit the scrambled pilot sequence using the same transmit power p_0, and that the transmit and receive processing gains of all nodes are g_t and g_r. Furthermore, according to the large-scale fading relationship f (d, e), it is assumed that the received signal power is inversely proportional to the distance d to the power x, satisfying the formulaWhere K and x are coefficients determined by the channel environment and may be obtained through a priori knowledge, in this embodiment, k=1 and x=3 are taken.
As above, the node S knows the received power of the neighbor node with a virtual distance of 1 hop and the corresponding scrambling sequence, the received power of the neighbor node with a virtual distance of 2 hops and the corresponding scrambling sequence, and the channel fading correlation parameters k=1 and x=3. According to the formulaAnd respectively calculating the distance between the nodes corresponding to the 1-hop neighbor node corresponding to the scrambling code receiving power and the distance between the nodes corresponding to the 2-hop neighbor node corresponding to the scrambling code receiving power. Counting the average distance of the 1-hop neighbor nodes and the average distance of the 2-hop neighbor nodes, and comparing themThe difference between the two is taken as the maximum transmission distance d_max of data transmission between the nodes.
The node S is based on the detected scrambling code information list S_t and the channel fading formula And calculating a maximum distance d_max of data transmission, quantizing the detected scrambling sequence with the number of hops between nodes, and dividing n according to the quantization>The 2-hop neighbor list is further divided into 3 packets, N (3) = [ R3, R8, R9, respectively]、N(4)＝[R4,R13,R14,R15]And N (5) = [ R5 ]]。
Based on the foregoing embodiment, an embodiment of the present invention provides a neighbor discovery system for executing the neighbor discovery method in the foregoing method embodiment. Referring to fig. 10, the system includes: a transmitting module 301 and/or a receiving module 302; a transmitting module 301, configured to scramble data with a scrambling code, and transmit the data to a receiving node, so that the receiving node extracts the scrambling code from the data, and detects energy of the scrambling code; establishing a neighbor list according to the energy of the scrambling code; a receiving module 302, configured to receive data sent from a sending node, where the data is scrambled by the sending node in advance with a scrambling code; extracting a scrambling code from the data, and detecting the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code.
An embodiment of the present invention provides an electronic device, as shown in fig. 11, including: a processor (processor) 501, a communication interface (Communications Interface) 502, a memory (memory) 503 and a communication bus 504, wherein the processor 501, the communication interface 502, and the memory 503 communicate with each other via the communication bus 504. The processor 501 may call a computer program on the memory 503 and executable on the processor 501 to perform the neighbor discovery method provided in the above embodiments, for example, including: scrambling the data by adopting a scrambling code, and transmitting the data to a receiving node so that the receiving node extracts the scrambling code from the data and detects the energy of the scrambling code; establishing a neighbor list according to the energy of the scrambling code; or receiving data transmitted from a transmitting node, wherein the data is scrambled by the transmitting node in advance by adopting a scrambling code; extracting a scrambling code from the data, and detecting the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code.
Further, the logic instructions in the memory 503 described above may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand alone product. Based on this understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method of the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
The embodiments of the present invention also provide a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, is implemented to perform the neighbor discovery method provided in the above embodiments, for example, including: scrambling the data by adopting a scrambling code, and transmitting the data to a receiving node so that the receiving node extracts the scrambling code from the data and detects the energy of the scrambling code; establishing a neighbor list according to the energy of the scrambling code; or receiving data transmitted from a transmitting node, wherein the data is scrambled by the transmitting node in advance by adopting a scrambling code; extracting a scrambling code from the data, and detecting the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code.
The above-described embodiments of electronic devices and the like are merely illustrative, in which elements illustrated as separate elements may or may not be physically separate, and elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
From the above description of the embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented by means of software plus necessary general hardware platforms, or of course may be implemented by means of hardware. Based on such understanding, the foregoing technical solutions may be embodied essentially or in part in the form of a software product, which may be stored in a computer-readable storage medium, such as a ROM/RAM, a magnetic disk, an optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform the various embodiments or some part of the methods of the embodiments.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (8)
1. A neighbor discovery method applied to a transmitting node, comprising:
scrambling data by adopting a scrambling code, and sending the data to a receiving node so that the receiving node extracts the scrambling code from the data and detects the energy of the scrambling code; establishing a neighbor list according to the energy of the scrambling code; the neighbor list is an n-hop neighbor list, and n is more than 2; correspondingly, establishing a neighbor list according to the energy of the scrambling code and the corresponding relation between the scrambling code and the user, including:
establishing a 1-hop neighbor list and a 2-hop neighbor list through a Hello message of 1 hop interacted with the neighbor node;
establishing the n-hop neighbor list according to the scrambling code information, wherein n is more than 2;
defining the distance between nodes based on the energy of the scrambling code, and dividing an n-hop neighbor list into m groups according to the distance according to the 1-hop neighbor list and the 2-hop neighbor list; the method specifically comprises the following steps:
according to the information of the 1-hop neighbor N (1) and the 2-hop neighbor N (2), counting the detected scrambling code power information E (1) and E (2) corresponding to the neighbor identities, and performing a statistical calculation to obtain a statistical average, a maximum value and a minimum value of the detected scrambling codes;
according to a wireless transmission large-scale fading model, establishing a relation f (d, e) between wireless transmission distance and received signal power, wherein d represents the distance between nodes, and e represents the signal power received by the nodes;
if the network node uses the same power p_0 to send a known specific sequence and the processing gains of the sending node and the receiving node are known, quantizing the scrambling code power E (N) detected in the scrambling code information list according to f (d, E), N (1), N (2), E (1) and E (2) information, wherein the actual distance is represented by the hop count between the nodes in the quantizing process;
and dividing the neighbor nodes which can be detected by the nodes into 1-hop neighbor N (1), 2-hop neighbor N (2), 3-hop neighbor N (3), … and (m+2) hop neighbor N (m+2) according to the scrambling code power E (N) detected in the quantized scrambling code information list, finishing the distance assessment and grouping of the neighbor nodes, and establishing a multi-hop neighbor list.
2. The method of claim 1, wherein scrambling the data with a scrambling code comprises:
if t0=t_1, then the data is scrambled using the following scrambling formula:
d’ = (d + p) mod 2
where t_0 is the duration of one chip and t_1 is the single bit duration of the binary data sequence; d is one bit of the data sequence, p is one bit of the scrambling sequence, and d' is one bit of the scrambled data sequence;
if t_0+.t_1, expanding each bit of the data sequence d and the scrambling sequence p into a plurality of identical bits such that the duration tx_0=tx_1 of one bit of the expanded sequence data sequence d_x and scrambling sequence p_x; the data is scrambled using the following scrambling formula:
d’ = (d_x + p_x) mod 2。
3. the method as recited in claim 1, further comprising:
periodically or according to the need, writing the collected neighbor information into the Hello message;
and sending the Hello message to a 1-hop neighbor node.
4. A neighbor discovery method applied to a receiving node, comprising:
receiving data transmitted from a transmitting node, wherein the data is scrambled by the transmitting node in advance by adopting a scrambling code;
extracting the scrambling code from the data and detecting the energy of the scrambling code;
establishing a neighbor list according to the energy of the scrambling code and the corresponding relation between the scrambling code and a user, wherein the neighbor list is an n-hop neighbor list, and n is more than 2; correspondingly, establishing a neighbor list according to the energy of the scrambling code and the corresponding relation between the scrambling code and the user, including:
establishing a 1-hop neighbor list and a 2-hop neighbor list through a Hello message of 1 hop interacted with the neighbor node;
establishing the n-hop neighbor list according to the scrambling code information, wherein n is more than 2;
defining the distance between nodes based on the energy of the scrambling code, and dividing an n-hop neighbor list into m groups according to the distance according to the 1-hop neighbor list and the 2-hop neighbor list; the method specifically comprises the following steps:
according to the information of the 1-hop neighbor N (1) and the 2-hop neighbor N (2), counting the detected scrambling code power information E (1) and E (2) corresponding to the neighbor identities, and performing a statistical calculation to obtain a statistical average, a maximum value and a minimum value of the detected scrambling codes;
according to a wireless transmission large-scale fading model, establishing a relation f (d, e) between wireless transmission distance and received signal power, wherein d represents the distance between nodes, and e represents the signal power received by the nodes;
if the network node uses the same power p_0 to send a known specific sequence and the processing gains of the sending node and the receiving node are known, quantizing the scrambling code power E (N) detected in the scrambling code information list according to f (d, E), N (1), N (2), E (1) and E (2) information, wherein the actual distance is represented by the hop count between the nodes in the quantizing process;
and dividing the neighbor nodes which can be detected by the nodes into 1-hop neighbor N (1), 2-hop neighbor N (2), 3-hop neighbor N (3), … and (m+2) hop neighbor N (m+2) according to the scrambling code power E (N) detected in the quantized scrambling code information list, finishing the distance assessment and grouping of the neighbor nodes, and establishing a multi-hop neighbor list.
5. The method of claim 4, further comprising, prior to extracting the scrambling code from the data:
based on a pre-agreed scrambling strategy, generating a scrambled specific sequence according to a pre-acquired specific sequence and a scrambling code;
performing correlation processing on the sequence and the received data to obtain a correlation value;
and if the correlation value exceeds a preset threshold, confirming that the data is scrambled by adopting the corresponding scrambling sequence.
6. A node, comprising a transmitting module and/or a receiving module;
the sending module is used for carrying out scrambling processing on data by adopting a scrambling code and sending the data to a receiving node so that the receiving node can extract the scrambling code from the data and detect the energy of the scrambling code; establishing a neighbor list according to the energy of the scrambling code; the neighbor list is an n-hop neighbor list, and n is more than 2; correspondingly, establishing a neighbor list according to the energy of the scrambling code and the corresponding relation between the scrambling code and the user, including:
establishing a 1-hop neighbor list and a 2-hop neighbor list through a Hello message of 1 hop interacted with the neighbor node;
establishing the n-hop neighbor list according to the scrambling code information, wherein n is more than 2;
defining the distance between nodes based on the energy of the scrambling code, and dividing an n-hop neighbor list into m groups according to the distance according to the 1-hop neighbor list and the 2-hop neighbor list; the method specifically comprises the following steps:
according to the information of the 1-hop neighbor N (1) and the 2-hop neighbor N (2), counting the detected scrambling code power information E (1) and E (2) corresponding to the neighbor identities, and performing a statistical calculation to obtain a statistical average, a maximum value and a minimum value of the detected scrambling codes;
according to a wireless transmission large-scale fading model, establishing a relation f (d, e) between wireless transmission distance and received signal power, wherein d represents the distance between nodes, and e represents the signal power received by the nodes;
if the network node uses the same power p_0 to send a known specific sequence and the processing gains of the sending node and the receiving node are known, quantizing the scrambling code power E (N) detected in the scrambling code information list according to f (d, E), N (1), N (2), E (1) and E (2) information, wherein the actual distance is represented by the hop count between the nodes in the quantizing process;
dividing neighbor nodes detectable by the nodes into 1-hop neighbor N (1), 2-hop neighbor N (2), 3-hop neighbor N (3), … and (m+2) hop neighbor N (m+2) according to scrambling code power E (N) detected in the quantized scrambling code information list, finishing distance evaluation and grouping of the neighbor nodes, and establishing a multi-hop neighbor list
The receiving module is used for receiving data sent from the sending node, and the data is scrambled by the sending node in advance by adopting a scrambling code; extracting the scrambling code from the data and detecting the energy of the scrambling code; and establishing a neighbor list according to the energy of the scrambling code.
7. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the steps of the neighbor discovery method of any one of claims 1 to 5 when the program is executed by the processor.
8. A non-transitory computer readable storage medium, having stored thereon a computer program, which when executed by a processor, implements the steps of the neighbor discovery method of any one of claims 1 to 5.
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